Shift device of a power take-off transmission

Abstract

A shift device for a power take-off transmission. An input shaft is connectable to an output shaft with three gear pairs. The output shaft has a recess, in which a PTO stub shaft can be reversibly introduced. A mechanism, actuated by a PTO stub shaft actuates a gearshift sleeve, provided on the output shaft and rotationally fixed to the output shaft, is provided on the output shaft. In one shift position of the gearshift sleeve is rotationally fixed to a gear wheel of a first gear pair. In another shift position of the gearshift sleeve no fixed connection exists between the gearshift sleeve and gear wheel of the first gear pair. By means of a further gearshift sleeve a rotationally fixed connection can be established with a gear wheel of the second or the third gear pair.

The invention claimed is: 
     
       1. A shift device of a power take-off (PTO) transmission of an agricultural utility vehicle, in particular a tractor, comprising an input shaft driven by an engine of the utility vehicle, and an output shaft, the input shaft being connectable to the output shaft by way of first, second and third gear pairs, in order to transmit torque from the input shaft to the output shaft via one of the three gear pairs, three gear wheels of the gear pairs being assigned to the input shaft, three gear wheels of the gear pairs being assigned to the output shaft, one gear wheel of a gear pair being rotationally fixed to one of the input shaft or the output shaft and the other gear wheel of the gear pair being rotationally fixable to one of the output shaft or the input shaft by a gearshift sleeve, the two gear wheels of a gear pair intermeshing with one another, the output shaft having a recess, in which a PTO stub shaft is reversibly introduced, a carrier component on which the gear wheels, embodied in the form of loose gears, of the second and third gear pair, are rotatably supported and wherein the carrier component can be rotationally fixed to one of the output shaft and the input shaft, a mechanism, actuated by a PTO stub shaft and which serves to actuate a gearshift sleeve, provided on the output shaft and rotationally fixed to the output shaft, being provided on the output shaft, the gearshift sleeve in one shift position of the gearshift sleeve being rotationally fixed to a gear wheel of a first gear pair, wherein in another shift position of the gearshift sleeve no rotationally fixed connection exists between the gearshift sleeve and gear wheel of the first gear pair and wherein by means of a further gearshift sleeve a rotationally fixed connection is established with one of a gear wheel of the second gear pair or with a gear wheel of the third gear. 
     
     
       2. The shift device as claimed in  claim 1 , wherein the further gearshift sleeve is rotationally fixed to the output shaft. 
     
     
       3. The shift device as claimed in  claim 2 , wherein the further gearshift sleeve is arranged between two gear wheels of the second and third gear pair and wherein the gear wheels are embodied as loose gears and are assigned to the output shaft. 
     
     
       4. The shift device as claimed in  claim 1 , wherein the further gearshift sleeve is assigned to the carrier component and wherein the further gearshift sleeve is rotationally fixed to the carrier component. 
     
     
       5. The shift device as claimed in  claim 4 , wherein the further gearshift sleeve is brought into rotationally fixed engagement with the loose gears of the second or third gear pair. 
     
     
       6. The shift device as claimed in  claim 1 , wherein the gear wheel of the first gear pair, which is brought into rotationally fixed engagement with the gearshift sleeve, is assigned to the output shaft. 
     
     
       7. The shift device as claimed in  claim 6 , wherein the gear wheel of the first gear pair is embodied as a loose gear. 
     
     
       8. The shift device as claimed in  claim 1 , wherein a further carrier component is assigned to the output shaft, on which at least two loose gears are rotatably supported. 
     
     
       9. The shift device as claimed in  claim 8 , wherein the gearshift sleeve rotationally fixed to the output shaft is in one shift position brought into rotationally fixed engagement with the further carrier component. 
     
     
       10. The shift device as claimed in  claim 8 , wherein a gearshift sleeve is assigned to the further carrier component and wherein the gearshift sleeve is rotationally fixed to the further carrier component. 
     
     
       11. The shift device as claimed in  claim 10 , wherein the gearshift sleeve is brought into rotationally fixed engagement with the loose gears supported on the further carrier component. 
     
     
       12. The shift device as claimed in  claim 1 , wherein the mechanism actuated by a PTO stub shaft comprises a component moveable in an axial direction, moved by means of a PTO stub shaft, and wherein the component is preferably biased, for example by means of a spring. 
     
     
       13. The shift device as claimed in  claim 12 , wherein the component is formed in such a way that it serves to move the gearshift sleeve of the output shaft, or wherein the component interacts with a further component, which serves to move the gearshift sleeve of the output shaft.